Natural Area Preservation City of Ann Arbor 1831 Traver Road Ann Arbor, Michigan 48105 Phone: 734•794•6627 Fax: 734•997•1072 E-mail: [email protected] Web site: www.a2gov.org/nap

INVASIVE PLANTS Garlic Mustard Alliaria petiolata

History

Garlic mustard (Alliaria petiolata) is a biennial herb in the mustard family which was introduced from Europe in the mid-1800s for food and medicinal purposes. The plant was thought to have many of the anti- bacterial qualities of the bulb its smell so resembles. Young plants are actually edible and tender and recipes are readily available on the internet. Garlic mustard has no natural predators or diseases in its

Alliaria petiolata non-native environment, is very adept at seed dispersal, and has a longer growing season than our natives. Theses characteristics, so often found in invasives, contribute to their rapid spread at the expense of native biodiversity. Over time its continued presence can result in a total loss of native groundcover in large areas and a decrease in over- all species diversity.

How Can I Identify It?

First year plants remain a rosette and reach a height of only a few inches. The rosette remains green throughout the winter and

GARLIC MUSTARD GARLIC MUSTARD develops into a mature fl owering plant the second year. In the second spring the bolted plant produces seeds in slender pods which are dispersed when the capsules burst open later in the summer. The seeds are tiny and easily spread to other areas in mud on shoes and animal feet and in fur. Rosette leaves are variable in size, kidney shaped and have palmate venation. They very much resemble wild violets, but when crushed give off a garlic odor. Stem leaves are alternate, toothed, and triangular, also giving off a distinctive garlic or onion odor when crushed. Flowering plants reach 1 – 4 feet in height. They produce small white fl owers with

F A C T S H E four petals in the shape of a cross that are mainly clustered at the top of the stem. The mission of Natural Area Preservation is to protect and restore Ann Arbor’s natural areas and to foster an environmental ethic among its citizens. How Can Garlic Mustard Be Controlled?

• NAP’s preferred method of control is hand-pulling.

• Prescribed burning is effective on seedling plants and fi rst year rosettes.

• For more information on control methods visit The Nature Conservancy website at: http://tncweeds.ucdavis.edu

This is a typical mustard family fl ower. Garlic mustard’s fl ower is 1/4 inch wide and is white. First year garlic mustard grows into a rosette and bolts in its second spring. The seed pod of garlic mustard is 2.5-7.5 cm long.

What Can I Do?

• If you see a small infestation, pull it. When pulling be sure to remove the root to prevent resprouting from root fragments. Pulled plants should be bagged and taken to a municipal compost facility to prevent the spread of seed.

• Stay on, and keep pets on, established roads and trails to prevent invasive seed Alliaria petiolata dispersal.

• After visiting an area that has garlic mustard, or other invasive weeds present, clean up before you leave the site! Make sure your clothes, shoes, vehicles, and pets are mud and/or seed free.

• Use plants native to southeastern Michigan in upcoming landscaping projects. NAP has a series of brochures to assist you in choosing native plants for your garden.

• Participate in NAP-sponsored volunteer workdays to remove garlic mustard and other

GARLIC MUSTARD GARLIC MUSTARD invasives from city natural areas.

• Learn to identify garlic mustard and other invasive weeds. Invasive herbaceous plants NAP would appreciate help with are:

garlic mustard (Alliaria petiolata) dame’s rocket (Hesperis matronalis) bittercress (Cardamine impatiens) golden archangel (Lamiastrum galeobdolon) knapweed (Centaurea spp.) common motherwort (Leonurus cardiaca) Canada thistle (Cirsium arvense) purple loosestrife (Lythrum salicaria) lily-of-the-valley (Convallaria majalis) Japanese knotweed (Fallopia japonica) F A C T S H E

Natural Area Preservation is funded by Ann Arbor’s voter-approved Repair and Restoration Millage.